A common medical examination is colonoscopy, in which a colonoscope is inserted into the colon. Typically the procedure is performed to visually check for the presence of polyps or other pre-cancerous or cancerous growths in the colon. Any polyps detected may be simultaneously removed.
To improve the likelihood of any polyps present in the colon being detected, it is necessary that the colon is substantially clear of faecal matter, to facilitate visual inspection of the colon. In order to achieve this, subjects who are to undergo colonoscopy must be prepared. Such preparation involves ingestion of a laxative to purge the colon. Typical laxative preparations for this purpose are sold under various product names such as Klean-Prep® and Moviprep.
Occasionally however subjects are inadequately prepared for colonoscopy, and too much faecal matter remains in the colon to permit reliable detection of small polyps which might nevertheless develop into cancers. In such circumstances, the colonoscopic investigation has to be halted and another appointment made. This is wasteful of medical resources and extremely inconvenient for the subject. At present no effective method has been described to detect such poor subject preparation prior to actual colonoscope insertion into the subject.